<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS </title>
    <style>
        div{
            width: 300px;
            height:300px;
            background: pink;
            display: inline;
        }
        span{
            /* 变成行内元素 */
            display: inline-block;
            display: block;
            display: none;
            width: 300px;
            height: 200px;
            background: yellow;
        }

    </style>
</head>
<body>
   <div>
       我是一个块级元素
   </div> 
   <span>我是一个span</span>
   <span>我是哈哈哈哈</span>
</body>
</html>